Head

Question 1

What are indications for a head CT scan

Answer 1

Stroke, TIA, hemorrhage, trauma, AVM, tumors, aneurysm, more…

Question 2

What is the patient position for Head CT

Answer 2

Supine, Head in holder, immobilized head. OML, or even more preferred, SOML parallell with gantry (chin tucked down)

Question 3

Why would having the OML or SOML be beneficial to the patient when scanning

Answer 3

It reduces the radiation exposure to the lens of the eye

Question 4

What type of scan is routine brain according to romans

Answer 4

Axial (step and shoot)

Question 5

What is included in a scan of the had

Answer 5

Skull base: Foramen magnum through petrous ridges
Temporal bones: just below mastoid process to just above petrous ridges
Sella: below sellar floor through dorsum sellae

Question 6

Why are beam hardening artifacts often seen in images of posterior fossa

Answer 6

Because the skull base is so dense

Question 7

How might artifacts be reduced for skull artifacts

Answer 7

thinner slices

Question 8

Is there CM for head CT routinely

Answer 8

no

Question 9

When might CM be used for head CT

Answer 9

Infections, neoplasms

Question 10

At what rate may someone hand inject CM for a head CT

Answer 10

~1ml/s

Question 11

What are the window settings for slices in post fossa

Answer 11

Soft tissue brain 160ww/40wl

Question 12

What are the window settings for slices above post fossa to vertex

Answer 12

Soft tissue brain 100ww/30wl

Question 13

What bone window settings

Answer 13

2500ww/400wl

Question 14

What blood window settings

Answer 14

200ww/60wl

Question 15

What is the relationship between brain density and edema after a stroke

Answer 15

As edema progresses brain density will decrease proportionately

Question 16

How much increase of water will result from a stroke after 6 hours

Answer 16

6% increase in water

Question 17

How many Hounsfield units will decrease after one hour post stroke

Answer 17

7-8HU

Question 18

What does ICH stand for

Answer 18

Intracranial Hemorrhage

Question 19

Where does density loss start in the head after an ICH

Answer 19

Density loss starts at the periphery/outskirts of the hematoma

Question 20

When does ICH begin to present as hyperdense

Answer 20

1-3 days post stroke

Question 21

When does the center become hyperdense and the concentric tissue become hyper/hypodense

Answer 21

4-10 days

Question 22

When will the center become isodense surrounded with hypodense tissue

Answer 22

11 days to 6 months

Question 23

When does the tissue become hypodense to normal

Answer 23

after approximately 6 months

Question 24

What is t-PA

Answer 24

Tissue plasminogen activator.
It is a pharmacologic treatment for acute ISCHEMIC stroke

Question 25

How soon should t-PA be given for effectiveness

Answer 25

within 3 hours of first sign of stroke

Question 26

Why can’t you give t-PA as soon as you suspect a stroke to prevent damage

Answer 26

Because if it is an ICH stroke it is contraindicated

Question 27

How can you differentiate between ischemic and ICH stroke

Answer 27

Noncontrast CT of the brain

Question 28

How are perfusion studies of the brain done

Answer 28

By administering CM and monitoring the passage of the iodinated contrast through the cerebral vasculature

Question 29

What are 3 type of aneurysm

Answer 29

Fusiform, Berry, Saccular